In order to inspect each semiconductor device formed on a wafer, a prober is used as an inspection apparatus. The prober includes a stage on which a wafer is mounted, and a probe card which can be disposed to face the stage. The probe card includes a plate-shaped base, and probes which are columnar contact terminals disposed on a surface of the base facing the stage to correspond to electrode pads of the semiconductor devices of the wafer.
In the prober, when the probe card is positioned to correspond to the wafer mounted on the stage, the probes of the probe card are brought into contact with the electrode pads of the semiconductor devices, and electricity is allowed to flow from the probes through electrical circuits in the semiconductor devices connected to the electrode pads, thereby inspecting a conduction state of the electrical circuits.
Recently, in view of improving the inspection efficiency, a probe card for inspecting a plurality of semiconductor devices formed on a single wafer at the same time has been developed. In this probe card, the probes of thousands, in some cases, tens of thousands are provided corresponding to the electrode pads of the semiconductor devices. The probe card has a rectangular parallelepiped-shaped housing having a plurality of probe holes, and the housing supports the probes inserted into the probe holes. Conventionally, it is known that the housing is formed by stacking thin metal plates and diffusion bonding the thin metal plates (see, e.g., International Patent Application Publication No. WO2009/104589 (corresponding to U.S. Patent Application Publication No. 2011/0006799A1)).
However, recently, a magnitude of the current flowing through the probe for inspection increases, whereas a diameter of each of the probes decreases along with miniaturization of the electrical circuit of the semiconductor device. For example, a large amount of current ranging from 1 A to 2 A may flow in round rod-shaped probes each having a diameter of several tens μm. In the probes, conductance for the current is reduced due to the decrease in diameter of each probe, so that the resistance of each of the probes increases. Accordingly, when a large amount of current flows through the probes, there is a concern that the probes generate a large amount of heat, and the temperature of the probes becomes very high, thereby resulting in degradation of the probes.